Bone positioning device and method

ABSTRACT

A method for positioning a bone cut on a bone may involve: coupling a bone cut positioning apparatus with a body bone; adjusting the positioning apparatus in a varus/valgus orientation relative to the body bone; adjusting the positioning apparatus in an anterior/posterior orientation relative to the body bone; and adjusting the positioning apparatus up or down to select a bone resection level.

CROSS REFERENCE TO RELATED APPLICATION

The present application is a continuation in part of U.S. patentapplication Ser. No. 12/616,747 filed Nov. 11, 2009 which is acontinuation of PCT/US2009/063015 filed on Nov. 2, 2009, the fulldisclosures of which are incorporated herein by reference.

BACKGROUND

Embodiments of the here described relate to medical/surgical devices,systems and methods. More specifically, embodiments here describedrelate to devices, systems and methods for enhancing a knee surgeryprocedure.

Approximately 550,000 total knee replacement surgeries (also referred toas total knee arthroplasty (“TKA”) are performed annually in the U.S.for the treatment of chronic knee pain and dysfunction. As the U.S. andworld populations become older and more obese, knee replacement surgerywill become even more common, as knee joints endure greater and greaterwear and tear from their increased loads and years of stress.Conventional TKA surgery is often very effective but also very invasiveand sometimes imprecise, thus leading to less than ideal outcomes.

The knee is generally defined as the point of articulation of the femurwith the tibia. Structures that make up the knee include the distalfemur, the proximal tibia, the patella, and the soft tissues within andsurrounding the knee joint. Four ligaments are especially important inthe functioning of the knee—the anterior cruciate ligament, theposterior cruciate ligament, the medial collateral ligament, and thelateral collateral ligament. In an arthritic knee, protective cartilageat the point of articulation of the femur with the tibia has been wornaway to allow the femur to directly contact the tibia. This bone-on-bonecontact causes significant pain and discomfort. The primary goals of aTKA procedure are to replace the distal end of the femur, the proximalend of the tibia, and often the inner surface of the patella withprosthetic parts to avoid bone-on-bone contact and provide smooth,well-aligned surfaces for joint movement, while also creating a stableknee joint that moves through a wide range of motion.

In a TKA surgery, the surgeon cuts open the knee, flips the patella boneout of the way, cuts bone from the distal end of the femur and from theproximal end of the tibia, and installs new, manmade, prosthetic endsonto the femur and tibia to form a new knee joint. In some TKAprocedures, the interior surface of the patella may also be covered witha prosthetic. Cutting open the knee, moving the patella, sawing off bonesegments, and implanting the manmade implants is a very invasive, thougheffective, procedure. Determining how to cut the ends of the femur andtibia to ensure proper alignment and balancing of ligament tension inthe new, prosthetic knee joint can be very challenging and ofteninvolves more art than science. An artificial knee joint in which theligament tension is not well balanced endures significantly more wearand tear than one that is properly balanced, and yet, this properbalance is very difficult to achieve. As a consequence, TKA surgeryperformed on younger patients typically needs to be redone one or moretimes during the patient's life.

Due to the invasiveness and imprecision of traditional TKA, there is aneed for improved techniques and devices in this field. A number ofminimally invasive (or “less invasive”) TKA techniques, involvingsmaller incision sizes and reduced trauma to the patient have beendeveloped in an effort to reduce patient recovery time. Some of theseminimally invasive techniques, as well as other innovations, have alsosought to enhance and/or facilitate TKA by making it more precise andrepeatable and thus, ideally, reducing wear and tear on artificial kneesand the need for repeat procedures. Improved techniques and deviceswould also mean enhanced outcomes for all TKA patients, with betterfunctioning of the knee joint and longer useful life of the artificialknee.

One of the greatest challenges in TKA surgery is to properly balanceligament tension, especially in the medial and lateral collateralligaments, through a full range of motion of the knee. The collateralligaments, which connect the distal femur and proximal tibia on themedial and lateral aspects of the knee, account for much of thestability and movement of the knee. If one of the collateral ligamentsis too lax or too tight relative to the other collateral ligament, theknee will typically be unstable, range of motion may be limited, thepatella may move (or “track”) improperly, and the femur and/or tibia maywear unevenly, leading to arthritis and pain. Uneven ligament tensionafter TKA surgery will typically cause joint instability and poorpatellar tracking, limited range of motion, and impaired function of theknee, as well as uneven, increased wear of the prosthetic device, whichoften necessitates repeat surgery. Thus, it is imperative for the short-and long-term success of a TKA procedure to achieve balanced ligamenttension in the knee through a full range of motion.

Balancing ligament tension during TKA surgery is complicated by the factthat the natural knee does not operate like a hinge moving about asingle axis. The knee exhibits dynamic external rotation of the tibiarelative to the femur as the knee moves from its flexed to its fullyextended position. This automatic rotation of the tibia occurs in theopposite direction when the knee is flexed from its fully extendedposition to produce an internal rotation of the tibia relative to thefemur. Thus, the natural knee exhibits a rotary laxity that allows thetibia to rotate through a limited internal and external arc during kneeflexion. In addition, the femur translates anteriorly and posteriorly asthe tibia is being flexed about it, bringing yet another movementvariable into the equation. Thus, the ligaments of the knee, along withthe femur, tibia and patella, create a truly dynamic bio-mechanism,making ligament tension balancing in TKA surgery extremely challenging.This challenge is even greater in minimally invasive TKA procedures, inwhich incisions are smaller than those made in “open” TKA surgeries.Additionally, the incision made during minimally invasive TKA surgery isbiased to the medial side, leaving the lateral side of specifically thedistal femur “closed” to access of front or end loaded surgicalinstruments

One way surgeons try to balance ligament tension during TKA proceduresis by cutting one or more ligaments to release tension from one part ofthe joint (“ligament release”). The disadvantage of ligament release,however, is that once a ligament is cut it cannot be regenerated, andthe ligaments of the knee provide much needed stability to the kneejoint.

Rather than or in addition to ligament release, the components of atotal knee prosthesis may be selected and positioned to balance ligamenttension. Since the femoral and tibial components of the knee prosthesisare attached to cut surfaces of the distal femur and proximal tibiarespectively, placement and orientation of the femoral and tibial bonecuts are very important for balancing knee ligament tension. As withligament release however, it is often very challenging to position thefemoral and tibial bone cuts and prosthetic components to provide idealligament tension through the range of motion. This is due primarily tothe complexity of motion about the knee, as described above, and thedifficulty of assessing and making the bone cuts during the procedure toachieve desired ligament tension through the full range of motion.

Improved methods and apparatus for facilitating and/or enhancing femoralbone cuts have been described by the assignee of the present applicationin, for example, U.S. Pat. Nos. 7,578,821 and 7,442,196. Few if anyinnovations have been made, however, to facilitate or enhance tibialbone cuts in a TKA procedure.

To make a tibial cut in a typical TKA procedure, an orthopedic surgeontypically uses a cutting block or cutting guide temporarily attached tothe front of the tibia via a rod that is typically attached to an ankleclamp at the distal end to the tibia (an extramedulary rod) and alignedapproximately with the mechanical axis of the anterior surface of thetibia. The cutting block is used to guide a surgical saw blade or rotarytool in making the tibial bone cut. Positioning such a cutting block,therefore, is crucial to forming well-positioned bone cuts forattachment of the tibial and femoral prosthetic components. The tibialcut is the foundation of a TKA, as it affects the spacing, alignment andbalance between the tibia and femur when the knee is in flexion (theflexion gap) the spacing, alignment and balance between the tibia andfemur when the knee is in extension (the extension gap) and all pointsof articulation between extension and flexion. Typically, the tibialcomponent of a knee prosthesis is positioned on a flat, horizontal cutsurface of the proximal tibia (at a 90 degree “varus/valgus” anglerelative to the long axis of the tibia), and the position andorientation of the tibial component typically do not vary greatly fromknee to knee. However, by making a cut on the tibia at 90 degrees to thelong axis of the bone, a bigger space is created laterally thanmedially, due to the tibia's natural approximately 3 degrees of varusslope. Furthermore, the “classic” 90-degree tibial bone cut is typicallymade by the surgeon simply approximating the 90-degree angle. Therefore,the usual cut made to the tibia in TKA is not necessarily ideal and ismade by approximation. Thus, improvements to the angle and precision ofthe tibial cut may improve the ligament balancing and overall result ofa TKA procedure.

Therefore, a need exists for improved devices, systems and methods forenhancing TKA surgery and specifically for enhancing and/or facilitatingthe positioning of one or more tibial bone cuts made during a TKAprocedure to accommodate a tibial prosthetic. Ideally, such devices,systems and methods would allow a physician to effectively select anangle at which to make a tibial bone cut and would help the physicianmore accurately make the cut at the selected angle. Such devices,systems and methods would also ideally be simple to use in conjunctionwith cutting guides, saw blades or burs, robotic and navigationalsystems, and/or any other equipment used by a surgeon in a TKAprocedure. At least some of these objectives will be met by variousembodiments of present invention.

BRIEF SUMMARY

The present invention relates to knee arthroplasty apparatus and method.The present invention provides devices, systems and methods forpositioning a bone cut which may be a bone cut on a tibia as part of aTKA or other knee surgery procedure. These devices, systems and methodsgenerally help a physician achieve balancing of ligaments during theknee surgery procedure, thus potentially enhancing the outcome of theprocedure and/or reducing wear and tear of an artificial knee jointimplanted during the procedure.

In one aspect, a method for positioning a bone cutting guide may involvecoupling a cutting guide positioning apparatus with a tibia, adjustingthe positioning apparatus in a varus/valgus orientation, adjusting thepositioning apparatus in an anterior/posterior orientation, adjustingthe positioning apparatus up or down to select a tibial bone resectionlevel, and contacting a cutting guide with the tibia, using the adjustedpositioning apparatus. In some embodiments, the method may furtherinclude emitting light in a linear configuration from the cutting guidepositioning device. In such embodiments, adjusting the apparatus in thevarus/valgus orientation may involve moving the light to shine alongapproximately a midline of an anterior surface of the tibia, andadjusting the apparatus in the anterior/posterior orientation mayinvolve moving the light to shine along approximately a midline of aside of the tibia. In one embodiment, the side of the tibia along whichlight is shone is the medial side. Optionally, this method may furtherinvolve swinging a swing arm of the cutting guide positioning apparatusapproximately 90 degrees between the steps of adjusting in thevarus/valgus orientation and adjusting in the anterior/posteriororientation. One embodiment further involves locking in the varus/valgusorientation before swinging the swing arm.

In some embodiments, the cutting guide is removably coupled with theguide positioning apparatus during the adjusting steps. In someembodiments, the method further includes attaching the cutting guide tothe tibia. Optionally, the method may further include removing thepositioning apparatus from the tibia and the cutting guide and making atleast one cut on the tibia guided by the cutting guide.

In one embodiment, adjusting the positioning apparatus up or down toselect a tibial bone resection level involves moving a resection leveladjustment member up or down to contact a stylus touching an uppersurface of the tibia and extending to a location anterior to and belowthe upper surface. In the present application, the “upper surface” ofthe tibia means the superior articular surface (or surfaces) of thetibia before any tibial bone cuts have been made. These superiorsurfaces are often referred to as the medial and lateral articularsurfaces or the medial and lateral facets of the tibia. For the purposesof this application, any of the terms “upper surface,” “articularsurface,” “facet” or “extreme proximal end” of the tibia may be usedinterchangeably. In one embodiment, the location anterior to and belowthe upper surface is between about 8 mm and about 11 mm below the uppersurface, and the upper surface is the lateral articular surface of thetibia.

In some embodiments, coupling the cutting guide positioning apparatuswith the tibia involves advancing the at least one hole in the apparatusover at least one reference pin attached to the tibia. In oneembodiment, two foot pads of the positioning device are advanced overtwo reference pins to contact the medial and lateral articular surfacesof the tibia.

In another aspect, a method for positioning a bone cutting guide on atibia may include: coupling a cutting guide positioning apparatus with atibia, wherein the positioning apparatus is coupled with a tibialcutting guide; emitting a light from the positioning apparatus;adjusting the positioning apparatus in a varus/valgus orientation toshine the light approximately along a midline of an anterior surface ofthe tibia; swinging a swing arm of the positioning apparatusapproximately 90 degrees to shine the light along a side of the tibia;adjusting the positioning apparatus in an anterior/posterior orientationto shine the light approximately along a midline of the side of thetibia; adjusting the positioning apparatus up or down to select a tibialbone resection level; and attaching the tibial cutting guide to thetibia, using the adjusted positioning apparatus.

In another aspect, a device for positioning a bone cut on a tibia mayinclude: a tibial attachment member; a coupler moveably attached to thetibial attachment member; a rotationally moveable arm rotationallyattached to the coupler; a swing arm coupled with the rotationallymoveable arm via an axle such that a free end of the swing arm swingsfrom an anterior position to a side position; a light emitting membercoupled with the swing arm at or near the free end for emitting lightalong the tibia; a varus/valgus adjustment member for adjusting therotationally moveable arm to direct the emitted light approximatelyalong a midline of an anterior surface of the tibia; ananterior/posterior adjustment member for adjusting the coupler in ananterior/posterior orientation relative to the tibial attachment memberto direct the emitted light approximately along a midline of a side ofthe tibia; and a tibial bone resection level adjustment member forselecting a level for resecting the tibia.

In some embodiments, the tibial attachment member may include at leastone foot pad for contacting an articular surface of an uncut tibia andat least one hole for passing the attachment member over a reference pinattached to the tibia. In one embodiment, the attachment member includesa medial articular surface footpad having a first hole and a lateralarticular surface footpad having a second hole.

In some embodiments, the light emitting member emits light in a linearor planar configuration. The side of the tibia is the medial side insome embodiments, and the swing arm rotates between a first position inwhich the light shines along the anterior surface of the tibia and asecond position in which the light shines along the medial side of thetibia. Alternatively, the lateral side of the tibia may be addressed inother embodiments. Some embodiments may further include a stylet coupledwith the tibial attachment member and configured to extend from an uppersurface of the tibia to a location anterior to and below the uppersurface. This tibial bone resection level adjustment member isadjustable to contact the tibial cutting guide with the stylus at thelocation. In some embodiments, the device further includes a tibialcutting guide holder, where adjustments of the adjustment members adjusta position of the cutting guide holder.

In another aspect, a system for positioning a tibial cutting guide on atibia may include a tibial cutting guide and a cutting guide positioningdevice. The positioning device may include: a tibial attachment member;a coupler moveably attached to the tibial attachment member; arotationally moveable arm rotationally attached to the coupler; a swingarm coupled with the rotationally moveable arm via an axle such that afree end of the swing arm swings from an anterior position to a sideposition; a light emitting member coupled with the swing arm at or nearthe free end for emitting light along the tibia; a varus/valgusadjustment member for adjusting the rotationally moveable arm to directthe emitted light approximately along a midline of an anterior surfaceof the tibia; an anterior/posterior adjustment member for adjusting thecoupler in an anterior/posterior orientation relative to the tibialattachment member to direct the emitted light approximately along amidline of a side of the tibia; a tibial bone resection level adjustmentmember for selecting a level for resecting the tibia; and a tibialcutting guide holder, where adjustments of the adjustment members adjusta position of the cutting guide holder.

Generally, the tibial cutting guide holder is moveable relative to therotationally moveable arm to move the tibial cutting guide into contactwith the tibia. In some embodiments, the system may further include atleast one reference pin for removably attaching the tibial attachmentmember of the guide positioning device to the tibia. Optionally, thesystem may further include at least one cutting guide fastener, such asa pin or rod, for attaching the tibial cutting guide to the tibia.

In another aspect, a method for positioning a bone cut on a tibia mayinvolve: coupling a bone cut positioning apparatus with a tibia;adjusting the positioning apparatus in a varus/valgus orientationrelative to the tibia; adjusting the positioning apparatus in ananterior/posterior orientation relative to the tibia; and adjusting thepositioning apparatus up or down to select a tibial bone resectionlevel. Optionally, the method may further include, before adjusting inthe varus/valgus orientation, attaching a laser light emitter to an armof the positioning apparatus and, before adjusting in theanterior/posterior orientation, detaching the laser light emitter fromthe arm and reattaching it at or near an opposite end of the arm. Insuch an embodiment, attaching the emitter to the positioning apparatusactivates the emitter such that it can emit laser light, adjusting theapparatus in the varus/valgus orientation comprises moving emitted laserlight to shine along approximately a midline of an anterior surface ofthe tibia, and adjusting the apparatus in the anterior/posteriororientation comprises moving emitted laser light to shine alongapproximately a midline of a side of the tibia. In some embodiments, theside of the tibia is the medial side.

In one embodiment, coupling the bone cut positioning apparatus with thetibia may involve coupling a tibial attachment member with a proximalend of the tibia and coupling the arm of the positioning apparatus withthe tibial attachment member. The arm extends around the tibiaapproximately 90 degrees from a first end of the arm anterior to thetibia to a second end of the arm lateral or medial to the tibia. In oneembodiment, the arm may attach to the tibial attachment member viamagnetic connection and the laser light emitter attaches to the arm viamagnetic connection.

Also in one exemplary embodiment, the adjusting steps comprise adjustinga screw coupled with a captured ball to move a portion of thepositioning apparatus about a pivot. The method may optionally furtherinvolve using the positioning apparatus to attach a bone cutting guideto the tibia. In such an embodiment, the method may further involveremoving the positioning apparatus from the tibia and the cutting guideand making at least one cut on the tibia guided by the cutting guide.

In another aspect, a method for positioning a bone cut on a tibia mayinvolve: coupling a bone cut positioning apparatus with a tibia;coupling a laser light emitter with the positioning apparatus at or nearone end of an arm of the apparatus, such that when the emitter iscoupled with the apparatus is emits light; adjusting the positioningapparatus in a varus/valgus orientation to shine the emitted lightapproximately along a midline of an anterior surface of the tibia;coupling the laser light emitter with the positioning apparatus at ornear an opposite end of the arm, such that when the emitter is coupledwith the apparatus is emits light; adjusting the positioning apparatusin an anterior/posterior orientation to shine the light approximatelyalong a midline of a side of the tibia; and adjusting the positioningapparatus up or down to select a tibial bone resection level.Optionally, in one embodiment the method may also include attaching atibial cutting guide to the tibia, using the adjusted positioningapparatus, removing the positioning apparatus from the tibia and thecutting guide, and making at least one cut on the tibia guided by thecutting guide.

In yet another aspect of the present invention, a device for positioninga bone cut on a tibia may include a tibial attachment member, an armattachable to the tibial attachment member and extending in an arc ofapproximately 90 degrees, a laser light emitter attachable to the arm ata first position at or near one end of the arm an a second position ator near an opposite end of the arm, a varus/valgus adjustment member formoving the arm to direct light emitted by the emitter in the firstposition approximately along a midline of an anterior surface of thetibia, an anterior/posterior adjustment member for moving the arm todirect light emitted by the emitter in the second position approximatelyalong a midline of a side of the tibia, and a bone resection leveladjustment member for selecting a level for resecting the tibia.

In some embodiments, the tibial attachment member may includeindependently movable medial and lateral feet for contacting the medialand lateral articular surfaces of the tibia. In one embodiment, thevarus/valgus adjustment member comprises a first captured ball andcaptured screw that rotates the tibial attachment member about a firstpivot point, and the anterior/posterior adjustment member comprises asecond capture ball and captured screw that rotates the tibialattachment member about a second pivot point. In one embodiment, thelaser light emitting member attaches to the arm at the first positionand the second position via magnetic force. In this or otherembodiments, the arm may attach to the tibial attachment member viamagnetic force.

One embodiment may further include a tibial cutting guide holder,wherein adjustments of the adjustment members adjust a position of thecutting guide holder. Some embodiments may further include a depth gaugecoupled with the bone resection level adjustment member.

In another aspect of the invention, a system for positioning a bone cuton a tibia may include a tibial cutting guide and a bone cut positioningdevice. The cutting guide positioning device may include: a tibialattachment member; an arm attachable to the tibial attachment member andextending in an arc of approximately 90 degrees; a laser light emitterattachable to the arm at a first position at or near one end of the arman a second position at or near an opposite end of the arm; avarus/valgus adjustment member for moving the arm to direct lightemitted by the emitter in the first position approximately along amidline of an anterior surface of the tibia; an anterior/posterioradjustment member for moving the arm to direct light emitted by theemitter in the second position approximately along a midline of a sideof the tibia; and a bone resection level adjustment member for selectinga level for resecting the tibia.

In one embodiment, the tibial cutting guide holder is moveable relativeto the arm to move the tibial cutting guide into contact with the tibia.Optionally, the system may further include at least one reference pinfor removably attaching the tibial attachment member of the guidepositioning device to the tibia. The system may also include at leastone cutting guide fastener for attaching the tibial cutting guide to thetibia. In some embodiments, the laser light emitting member emits lightin a linear or planar configuration that may be directed along thetibia. In some embodiments, the laser light emitting member attaches tothe arm at the first position and the second position via magneticforce. In some embodiments, the arm attaches to the tibial attachmentmember via magnetic force. Some embodiments may further include a depthgauge attachable to the cutting guide positioning device. In someembodiments, the depth gauge comprises a slidable member adjustable bymoving the bone resection level adjustment member and including at leastone indicator to indicate to a user when a desired bone cut level hasbeen reached. In some embodiments, the at least one depth gaugecomprises multiple depth gauges provided as a set, each gauge having anindicator at a different depth for facilitating a different boneresection level. For example, in one embodiment, the multiple depthgauges comprise three gauges having indicators at 3 mm, 9 mm and 10 mmof depth. In various embodiments, the indicator on a depth gauge mayinclude but is not limited to an LED, a colored marker, a reflectivemarker and/or a tactile element.

For a further understanding of the nature and advantages of theinvention, reference should be made to the following description takenin conjunction with the accompanying figures. However, each of thefigures is provided for the purpose of illustration and description onlyand is not intended to limit the scope of the embodiments of the presentinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a perspective view of a bone cut positioning system coupledwith a proximal end of a tibia, according to one embodiment;

FIG. 1B is a side view of the system and tibia of FIG. 1A;

FIG. 1C is an exploded perspective view of the system of FIGS. 1A and1B;

FIG. 1D is an exploded view of a portion of the system of FIGS. 1A-1C;

FIGS. 2A-2J illustrate a method for positioning a bone cut using a bonecut positioning system, according to one embodiment;

FIG. 3A is a perspective view of a bone cut positioning system coupledwith a proximal end of a tibia, according to an alternative embodiment;

FIGS. 3B and 3C are perspective and posterior views, respectively, ofthe positioning system of FIG. 3A with the addition of an optionalstylet;

FIG. 3D is a perspective view of a tibia with attached cutting guide andtibial bone saw blade in place after positioning of the cutting guideusing the positioning system of FIGS. 3A-3C;

FIGS. 4A-4I are various views of a tibial attachment member of a bonecut positioning system according to one embodiment;

FIGS. 5A-5J are various views of a bone cut positioning system accordingto an alternative embodiment;

FIG. 6 is a side view of a tibial pin positioning adjustment memberaccording to one embodiment;

FIG. 7 is a perspective view of a depth guide of one embodiment of abone cut positioning system;

FIGS. 8A-8D demonstrate a method for placing guide pins and a guideblock using a bone cute positioning system according to one embodiment;

FIGS. 9A-9D are various views of a tibial cut check device according toone embodiment;

FIGS. 10A-10D show a depth gauge device for a bone cut positioningsystem according to one embodiment; and

FIGS. 11A-11E show a depth gauge device for a bone cut positioningsystem according to an alternative embodiment.

DETAILED DESCRIPTION OF THE INVENTION

The devices, systems and methods described below may be used in variousembodiments to enhance and/or facilitate a total knee arthroplasty (TKA)procedure, a partial knee arthroplasty procedure, or any other suitableknee surgery procedure in which one or more cuts are made on a tibia,typically a proximal end of a tibia. Generally, the embodimentsdescribed herein provide a means for positioning a bone cut on a tibia.Although the following description may frequently refer to TKAprocedures, the described embodiments may also be used for partial kneearthroplasty procedures or other knee procedures in which tibial bonecuts are made.

Referring to FIG. 1A, one embodiment of a bone cut positioning system100 is shown attached to a tibia T. In this view, the tibia T is of aright leg and is in an anterior (front) facing orientation, with thelateral side L of the tibia T toward the left side of the figure and themedial side M of the tibia toward the right side of the figure.

FIG. 1B shows system 100 in place with the medial side M of the tibia Tfacing out of the page and the system 100 rotated to address the medialside M, as will be explained in more detail below. FIG. 1C shows anexploded view of system, and FIG. 1D shows an exploded view of part ofsystem 100.

In the embodiment of FIGS. 1A-1D, system 100 for enhancing and/orfacilitating positioning a bone cut on a tibia T includes a bone cuttingguide 112 (or “guide block”) and a bone cut positioning device 110. Inalternative embodiments, positioning device 110 may be adapted toposition a bone cut without using cutting guide 112, or by using adifferent variation of cutting guide 112. In various embodiments, bonecutting guide 112 may be any currently available or subsequentlydeveloped bone cutting guide 112. Because bone cutting guides or guideblocks are well known in the art, they will not be described furtherherein. In various embodiments, bone cutting guide 112 may be providedas part of the system 100 or alternatively may be available separately.

In some embodiments, bone cut positioning device 110 may be coupled tothe tibia T via a tibial reference pin 102 (or “tibial pin”) insertedinto the tibia T. Pin 102 may be part of system 100 or may be availableseparately, in various embodiments. Pin 102 may be used in place ofextramedulary rods.

In the embodiment of FIGS. 1A-1D, bone cut positioning device 110includes a number of component parts, some of which may be more easilyviewed in FIGS. 1C and 1D. As shown in FIG. 1D, for example, positioningdevice 110 may include a tibial attachment member 114 that attachesdirectly to the tibia T via a hole 115 for accepting pin 102 and isrotationally moveable relative to the tibia T during use of positioningdevice 110. In this embodiment, tibial attachment member 114 includestwo foot pads—a right foot pad 114 a and a left footpad 114 b—forcontacting the proximal end of the tibia T. In alternative embodiments,one foot pad or more than two foot pads may be used. Positioning device110 also includes a coupler 106, which attaches a rotationally moveablearm 128 to tibial attachment member 114. A varus/valgus adjustmentmember 116 and an anterior/posterior adjustment member 104 (or “tibialslope adjustment member”) move members 128 and 106 relative to thetibial attachment member 114 to adjust the orientations of device 110and thus adjust the orientation of cutting guide 112 relative to thetibia T. In the embodiment shown, adjustment members 116, 104 arethreaded, bolt-like apparatus that are adjustable by an adjustmentdevice 124, such as but not limited to the Allen wrench shown in thefigure. In alternative embodiments, any other suitable adjustmentapparatus may be used for adjusting coupler 106 relative to tibialattachment member 114, such as rack and pinion gears, ring and piniongears or the like.

Rotationally moveable arm 128 may be rotated during a positioningprocess by adjusting adjustment member 116, though rotationally moveablearm 128 remains anterior to the tibia T during the positioningprocedure. Rotationally moveable arm 128 includes a slot 108 forreceiving a tibial bone resection level adjustment member 132, which iscoupled with a cutting guide attachment member 134, which in turn isremovably coupled with cutting guide 112. In one embodiment, tibial boneresection level adjustment member 132 may comprise a bolt-like apparatuswith threads and an adjustment knob, as pictured in FIGS. 1A-1D. Slot108 is configured to allow resection level adjustment member 132 toslide horizontally back and forth to move cutting guide 112 toward andaway from the tibia T and to move vertically up and down to select aheight (i.e., bone resection level) at which cutting guide 112 willcreate a bone resection plane to be established by a saw blade upon thetibia T. In some embodiments, resection level adjustment member 132 maybe locked or set at a desired level after adjustment.

Rotationally moveable arm 128 is coupled with a swing arm 126 (or“swivel arm”) at a pivot point via an axle 129. Optionally, a lock screw130 may be included to lock swing arm 126 relative to rotationallymoveable arm 128, typically in either a 0° (facing anterior tibia) or a90° (facing side tibia) orientation. Swing arm 126, in turn, is coupledwith a light emitting apparatus 120, generally including a light sourceand in some embodiments an on/off switch 121. Light emitting apparatus120 is capable of directing a plane of light 122 (FIGS. 1A and 1B)toward a surface of a tibia T for guiding orientation and adjustment ofdevice 110. In alternative embodiments, the light emitted by lightemitting apparatus may be in the form of a beam, fan, or any othersuitable linear configuration for shining along a length of a tibia. Insome embodiments, light emitting apparatus 120 may be tilted by a userto ensure that the plane of light 122 is directed along the tibialsurface.

Swing arm 126 may be configured to rotate from the 0° position towardeither side to the 90° position. In one embodiment, for example, swingarm 126 may be rotated from the 0° position to a 90° position facing amedial side of a tibia on a first knee of a patient and may be rotatedin the opposite direction on the second knee of the patient so that the90° position also faces the medial side of that second tibia. Inalternative embodiments, the 90° position may be either a medial side ora lateral side of a tibia.

Coupler 106 may be adjusted in the anterior/posterior orientation viaadjustments to an anterior/posterior adjustment member 104. In variousembodiments, coupler 106 may be locked in the anterior/posteriororientation as well as or alternative to locking in the varus/valgusorientation. In some embodiments, adjustment members 116, 104 andlocking member 118 may all be screws, bolts or other threaded adjustmentmembers. In the embodiment shown, adjustment members 116, 104 andlocking member 118 are adjusted using Allen wrench 124, although inalternative embodiments any suitable adjustment device may be used, suchas a screw driver, wrench, fingers or the like.

Referring to FIGS. 1C and 1D, tibial bone resection adjustment member132 passes through slot 108 and attaches to cutting guide attachmentmember 134. Cutting guide attachment member 134 is configured as aplatform for holding cutting guide 112. In alternative embodiments,attachment member 134 may have any other suitable shape, size orconfiguration for removably coupling with one or various differentcutting guides.

The various components of bone cut positioning device 110 may bemanufactured from any suitable materials. For example, in someembodiments many of the components may be made of stainless steel orother metal, which other components may be plastic. In a typicalembodiment, all materials of device 110 may be sterilizable by commonlyused sterilization techniques, such as gamma irradiation, EtOsterilization and the like. Any adjustment screws, bolts, trunions orthe like may be substituted with similar adjustment means in alternativeembodiments, and adjustment devices such as Allen wrenches, screwdrivers and the like may be likewise substituted.

Referring now to FIGS. 2A-2J, a method is shown for positioning a bonecut on a tibia as part of a TKA or other knee surgery procedureaccording to one embodiment. As shown in a perspective view in FIG. 2A,bone cut positioning system 100 (bone cut positioning device 110 andcutting guide 112) may first be coupled with the tibia T via referencepin 102. When initially attached, bone cut positioning device 110 may beadjusted such that swing arm 126 positions light emitting device 120 atthe 0° angle, i.e., facing the anterior surface of the tibia T. Plane oflight 122 may be generally directed toward the anterior surface of thetibia T but may not be initially aligned to shine directly along themidline of the anterior surface.

As shown in FIGS. 2B and 2C, adjustment device 124 may be used to adjustvarus/valgus adjustment member 116, which in turn moves rotationallymoveable arm 128, swing arm 126 and light emitting member 120 in thevarus/valgus orientation. This movement adjusts the direction of planeof light 122 such that, as shown in FIG. 2C, light 122 may be directedapproximately along a midline of the anterior surface of the tibia T.Positioning device 110 is configured such that when plane of light 122is directed along approximately the midline of the anterior surface ofthe tibia T, as in FIG. 2C, cutting guide 112 is oriented in a desirablevarus/valgus orientation for making a tibial bone cut.

In one embodiment, and with reference now to FIG. 2D, adjustment device124 may next be used to lock in the varus/valgus adjustment ofpositioning device 110 via locking member 118. In alternativeembodiments, it may not be necessary to lock in the varus/valgusadjustment or the adjustment may be locked in automatically by anautomatic locking mechanism of device 110.

Referring to FIG. 2E, adjustment device 124 may next be coupled withanterior/posterior adjustment member 104. As shown in FIG. 2F, swing arm126 may be rotated about axle 129 (now visible) approximately 90° toposition light illuminating member 120 to direct plane of light 122along the medial side M of the tibia T. Although in an alternativeembodiment the lateral side L of the tibia T may be used for the bonecut positioning method, the medial side M is generally the preferredside for orienting and positioning device 110 and cutting guide 112.

As shown in FIG. 2G, adjustment device 124 may next be used to adjustanterior/posterior adjustment member 104 (not visible) and thus movecoupler 106, rotationally moveable arm 128, swing arm 126 and lightemitting member 120 to direct plane of light 122 approximately along themidline of the medial side M of the tibia T. As seen when comparingFIGS. 2F and 2G, as positioning device 110 is adjusted, cutting guide's112 orientation relative to the tibia is also adjusted. In oneembodiment, the anterior/posterior orientation may be locked in placevia a second locking member. However, this second locking is optionaland is not included in the embodiment shown in the figures.

Referring now to FIG. 2H, once varus/valgus and anterior/posterioradjustments have been made, tibial bone resection level adjustmentmember 132 may turned to move cutting guide 112 up or down relative tothe tibia T (hollow-tipped arrow shows upward movement). This upward ordownward adjustment may be made by the physician, depending on a desiredlocation of the cutting guide relative to the tibia T. Adjustment member132 may then be slid along slot 108 (not visible) to move cutting guide112 into contact with the tibia T (solid-tipped arrows show horizontalmovement).

Once cutting guide 112 is in contact with the tibia T, it may beattached to the tibia T using one or more bone attachment pins 140 (or“rods”), as shown in FIG. 2I. Finally, as shown in FIG. 2J, positioningdevice 110 may be removed, leaving behind cutting guide 112, which thephysician may then use to guide a saw blade to cut off a slice of bonefrom the proximal end of the tibia T. Once the tibial bone cut is made,cutting guide 112 is removed and the rest of the TKA or other kneesurgery procedure is performed. As mentioned above, in alternativeembodiments, positioning device 110 may be used to mark or otherwiseguide a tibial bone cut, thus removing the need for cutting guide 112.In either case, positioning device 110 helps position tibial bone cutsto enhance ligament balancing during a TKA or other knee surgeryprocedure, and to assure proper alignment of the tibia to the femur.

Referring now to FIGS. 3A-3C, another embodiment of a system 200 forpositioning a tibial bone cut is shown. Many of the features of system200 are the same or similar to those described above in reference toFIGS. 1A-1D, and thus those features will not be described here again.In this embodiment, as best seen the posterior view of FIG. 3C, a tibialattachment member 213 includes a lateral attachment member 213 a with alateral footpad 214 b and a medial attachment member 213 b with a medialfootpad 214 b. Attachment members 213 a, 213 b are attached to a tibia Tvia two reference pins 203, and a coupler 206 is attached to attachmentmembers 213 a, 213 b. As shown in FIG. 3A, in some embodiments,attachment members 213 a, 213 b may be locked to coupler 206 using alock screw 215 or other locking mechanism. As also shown in FIGS. 3A and3C, coupler may in some embodiments also be attached to the tibia T viaanother reference pin 202.

System 200 includes an alternative cutting guide holder 234, whichincludes two rods 235 on which cutting guide 212 rests duringadjustments of system 200 to select a desired location for cutting guide212. As in the previously described embodiment, holder 234 is attachedto a bone cut resection level adjustment member 232 configured to moveholder 234 up and/or down to select a desired resection level.Adjustment member 232 can also move back and forth through a slot on therotationally moveable arm, as previously described, to bring cuttingguide 212 into or out of contact with the tibia T.

With reference to FIGS. 3B and 3C, in some embodiments, system 200 mayinclude a stylus 250 for determining a bone cut resection level. Stylus250 is coupled with tibial attachment member 213 and/or coupler 206,according to various embodiments. As seen in FIG. 3C, stylus 250contacts one of the articular surfaces of the tibia via a tibial contact254. In the embodiment shown, the lateral articular surface iscontacted. As seen in FIG. 3B, stylus 250 wraps around the tibia T andextends to a resection level bumper 252, against which cutting guide 212may be adjusted to select a desired bone resection level. In thisembodiment, wherein tibial contact 254 contacts the lateral articularsurface of the tibia T, the contact point of bumper 252 may be betweenabout 8 mm and about 11 mm below the lateral articular surface, and insome embodiments between about 9 mm and about 10 mm below the lateralarticular surface. If stylus 250 is instead coupled with a medialarticular surface, bumper 252 will likely extend to a different levelbelow the medial articular surface. Generally, stylus 250 is used tohelp select a desired tibial resection level at which to place cuttingguide 212 by adjusting adjustment member 232.

Referring now to FIG. 3D, tibial cutting guide 212 is shown attached tothe tibia T via two attachment rods 270 (or “pins”). In alternativeembodiments, only one rod 270, more than two rods 270, or any suitablealternative fasteners may be used to attach cutting guide 212 to thetibia T. After cutting guide 212 is attached, a tibial bone saw blade260 is then used to make the bone cut (or multiple cuts) on the proximaltibia T. Blade 260 is attached to a bone saw (not shown) to make thecut. Once the tibial bone cut is made, cutting guide 212 is removed andthe remainder of the TKA or other knee arthroplasty procedure isperformed.

Referring now to FIGS. 4A-4H, a tibial attachment member 300 of a tibialbone cut positioning system according to one embodiment is shown. Inthis embodiment, as shown in FIG. 4A, tibial attachment member 300includes three fixation holes 302, which are offset relative to oneanother to provide enhanced stability to attachment member 300 whenattached to a tibia. Tibial attachment member 300 may further includetwo tibial contact feet 304 (FIG. 4C) for contacting medial and lateralarticular surfaces of the tibia. These contact feet 304 may beindependently movable and/or lockable in some embodiments. Feet 304 mayalso be designed to slip under the femur and provide consistent contactwith the tibia, as shown in FIG. 4B.

FIGS. 4D-4F are top, side and cross-sectional views, respectively, oftibial attachment member 300, showing tibial slope (or“anterior/posterior”) adjustment apparatus 306, 308, 310. In thecross-sectional view of FIG. 4F, adjustment apparatus can be seen toinclude a captured ball 306, a captured screw 308 and a pivot 310. Inthis embodiment, captured screw 308 may be adjusted relative to capturedball 306 to move tibial attachment member 300 about pivot 310 and thusadjust the tibial slope (or “anterior/posterior orientation”) of tibialattachment member 300. In alternative embodiments, other adjustmentmechanisms may be used, and thus this embodiment is provided as anexample only.

FIGS. 4G-4I are top, side and cross-sectional view, respectively, oftibial attachment member 300, showing varus/valgus (or “medial/lateral”)adjustment apparatus 312, 314, 316. In the cross-sectional view of FIG.4I, taken through dotted line A-A in FIG. 4H, adjustment apparatus canbe seen to include a captured ball 312, a captured screw 314 and a pivot316, similar to the adjustment apparatus for tibial slope. Again,captured screw 314 may be adjusted relative to captured ball 312 to movetibial attachment member 300 about pivot 316 and thus adjust thevarus/valgus (or “anterior/posterior”) orientation of tibial attachmentmember 300. Again, in alternative embodiments, other adjustmentmechanisms may be used.

Referring now to FIGS. 5A-5I, an alternative embodiment of a tibial bonecut positioning system 320 is shown in various views. As shown in FIG.5A, in one embodiment, bone cut positioning system 320 may include atibial attachment member 322 removably couplable with an arm 328.Attachment member 322 and arm 328 may be coupled with one another viaany acceptable means in various embodiments. For example, in theembodiment shown, attachment member 322 may include a magneticattachment plate 324 that mates with a magnetic attachment plate on arm328. Pins 326 on the magnetic attachment plate of arm 328 may fit intoholes on the magnetic attachment plate 324 of attachment member 322.This configuration may facilitate removal and attachment of arm 328 toattachment member 322, thus making the overall system 320 lesscumbersome and easier to use.

Turning now to FIG. 5B, arm 328 generally includes a first attachmentpoint 330 a and a second attachment point 330 b for removably attachinga laser light emitter 340 (FIG. 5C) to arm 328. As shown, arm 328generally extends approximately 90 degrees about an arc, although arm328 itself need not be shaped as an arc. Attachment points 330 a, 330 bare located at or near opposite ends of arm 328, so that when arm 328 isattached to tibial attachment member 322, attachment points 330 a, 330 bare generally positioned so that an attached laser light emitter 340will address anterior and side aspects of a tibia (either medial orlateral). Attachment points 330 a, 330 b may attach with laser lightemitter 340 via magnetic force attachment, similar to the attachment ofarm 328 to tibial attachment member 322. In one embodiment, each end ofarm 328 may include one attachment point 330 a, 330 b (or “magneticcontact area”), as shown in FIG. 5B. Alternatively, as shown in FIG. 5I,another embodiment of an arm 322 may include attachment points 334 (or“magnetic contact areas”) at each end of arm 322. Alternatively, asshown in FIG. 5J, another embodiment may include magnetic attachmentpoints to a rotational swing arm 126. In yet other embodiments, lightemitter 340 may attach to arm 328 via any other suitable attachmentmeans.

FIGS. 5D-5H show laser light emitter 340 attached at various points toarm and emitting light 342 toward a tibia from various angles. In oneembodiment, light emitter 340 may not be turned on until it is attachedto arm 328 via its magnetic attachment (or other attachment means). Thiscontrol make act as a safety mechanism to prevent light emitter 340 frombeing turned on prematurely or from being left on accidentally afteruse. In one embodiment, light emitter 340 may turn on automatically whenattached to arm 328 and turned off automatically when removed from arm328. The simple removability and attachment of light emitter 340relative to arm 328 allows for easy movement from tibial slopeadjustment to varus/valgus adjustment and vice versa. FIGS. 5E and 5Fshow varus/valgus alignment positions, and FIGS. 5G and 5H show tibialslope alignment positions.

Turning now to FIG. 6, in one embodiment a bone resection leveladjustment member of a bone cut positioning system may include anadjustment knob 344 coupled with a pin template 346 (or “pin guidingmember”). Each turn of knob 344 may drop or raise pin template 346 by aknown distance, such as 1 mm in one embodiment. As shown in FIG. 7, someembodiments may further include a depth gauge 348, which may referenceoff of the trough of the medial or lateral compartment of the tibia forhelping a user determine a depth of the bone cut to be made.

FIGS. 8A-8D demonstrate a method according to one embodiment for makinga bone cut on a tibia using a bone cut positioning system 320. As shownin FIG. 8A, once tibial slope, varus/valgus and bone cut leveladjustments have been made via system 320, pins 350 may be insertedthrough holes on pin template 346 and drilled into the tibia. As shownin FIG. 8B, arm 328 and the components of system 320 attached to arm 328may be removed from tibial attachment member 322. As shown in FIGS. 8Cand 8D, a bone cutting guide 352 may then be advanced over pins 350, anda bone saw 354 may be used to make the tibial bone cut.

Referring now to FIGS. 9A-9D, one optional feature of a bone cutpositioning system may be a tibial cut check device 360. In use, cutcheck device 360 is attached to the cut surface of the tibia, either viapins 350 or by holding manually by a user. Visualization features 362 ofcut check device 360 may then be used to assess the tibial cut. As shownin FIG. 9B, cut check device 360 may include an attachment plate 364 sothat it can be attached to arm 328 using the same attachment means astibial attachment device 322. As shown in FIGS. 9C and 9D, laser lightemitter 340 can then be used with cut check device 360 coupled with arm328 to check tibial slope and varus/valgus alignment. If the desiredalignments were not achieved with the initial cut, additional cuts maybe made and checked again until the desired result is achieved.

With reference now to FIGS. 10A-10D, another optional feature of a bonecut positioning system may be one or more depth gauges 370 for helping auser select a desired tibial bone resection level. In one embodiment,for example, multiple depth gauges 370 for different bone cut resectionlevels may be provided. As shown, for example, one embodiment mayinclude a 3 mm gauge 372 a, a 9 mm gauge 370 b, and a 10 mm gauge 370 c,for measuring a bone resection level. In this embodiment, each gauge 370includes an LED 372 at the desired level of bone resection—i.e., a 3 mmLED 372 a, a 9 mm LED 372 b, and a 10 mm LED 372 c.

As shown in FIG. 10B, depth gauge 370 b may be placed into a depth arm374, which is attached to tibial attachment member 322 and includes anaperture 376. As discussed previously, a pin template 346 is generallyincluded in the bone cut positioning system and is attached to arm 328and adjustable via knob 344. As shown in FIG. 10C, turning knob 344 willraise pin template 346 to contact one end of depth gauge 370 b. As shownin FIG. 10D, continuing to turn know 344 will continue to raise pintemplate 346 and thus will push depth gauge 370 b upward, so that LED372 b will be visible through aperture 376. At this point, when LED 372b is visible through aperture 376, the user knows the desired depth ofbone cut has been reached.

In another embodiment, and with reference now to FIGS. 11A-11E, depthgauges of various heights 380 a, 380 b, 380 c may include colored,reflective or otherwise distinguishable markers 382 a, 382 b, 382 c. Ofcourse, in this or the previous embodiment, any suitable number of depthgauges 380 may be provided, from one to any unlimited number. In someembodiments, multiple depth gauges 380 may be provided as a set or kit,while in other embodiments, depth gauges may be provided individually.Also, although the examples of LEDs 372 are shown in depth gauges 370 a,370 b, 370 c, and circumferential markers 382 are shown in depth gauges380 a, 380 b, 380 c, in alternative embodiments any suitablevisualization, tactile or other feedback elements may be used tofacilitate a user's confirmation that a desired depth has been achieved,such as but not limited to one or more bumps for tactile feedback,colored dots for visualization, or a beeping noise indicating desireddepth. Thus, the exemplary embodiments of FIGS. 10A-10D and 11A-11E areprovided for exemplary purposes only.

Turning now to FIG. 11B, in this embodiment, as in the previous one,gauge 380 a may be inserted into a depth arm 384 having an aperture 386(in this embodiment slot-shaped rather than round). As shown in FIGS.11C and 11D, knob 344 may then be adjusted to bring pin template 346into contact with one end of gauge 380 a (FIG. 11C) and then to push upgauge 380 a until marker 382 a shows through aperture 386. If the userturns knob 344 too far, as in FIG. 11E, marker 382 b is no longervisible through aperture 386, so user will know to turn knob in theopposite direction to adjust the bone cut height.

The present invention may be embodied in other specific forms withoutdeparting from the essential characteristics thereof. For example, inalternative embodiments method steps may be deleted, added or performedin a different order than that described above. In one embodiment, forexample, it may be possible to perform the anterior/posterior adjustmentprior to the varus/valgus adjustment. Thus, the embodiments describedabove as well as alternative embodiments and equivalents are intended tobe included within the scope of the present invention, which is setforth in the following claims. While the description has been geared towork with a tibia, the device, method and system may be used with otherbones. All elements and steps described are preferably included but maybe omitted or replaced with other elements and steps.

Broadly, this writing discloses at least the following concepts.

CONCEPT 1. A method for positioning a bone cut on a tibia, the methodcomprising:

-   -   coupling a bone cut positioning apparatus with a tibia;    -   adjusting the positioning apparatus in a varus/valgus        orientation relative to the tibia;    -   adjusting the positioning apparatus in an anterior/posterior        orientation relative to the tibia; and    -   adjusting the positioning apparatus up or down to select a        tibial bone resection level.        CONCEPT 2. A method as in concept 1, further comprising:    -   before adjusting in the varus/valgus orientation, attaching a        laser light emitter to an arm of the positioning apparatus,        wherein attaching the emitter to the positioning apparatus        activates the emitter such that it can emit laser light and        wherein adjusting the apparatus in the varus/valgus orientation        comprises moving emitted laser light to shine along        approximately a midline of an anterior surface of the tibia; and    -   before adjusting in the anterior/posterior orientation,        detaching the laser light emitter from the arm and reattaching        it at or near an opposite end of the arm, wherein adjusting the        apparatus in the anterior/posterior orientation comprises moving        emitted laser light to shine along approximately a midline of a        side of the tibia.        CONCEPT 3. A method as in concept 2, wherein the side of the        tibia comprises a medial side.        CONCEPT 4. A method as in concept 2, wherein coupling the bone        cut positioning apparatus with the tibia comprises:    -   coupling a tibial attachment member with a proximal end of the        tibia; and    -   coupling the arm of the positioning apparatus with the tibial        attachment member, wherein the arm extends around the tibia        approximately 90 degrees from a first end of the arm anterior to        the tibia to a second end of the arm lateral or medial to the        tibia.        CONCEPT 5. A method as in concept 4, wherein the arm attaches to        the tibial attachment member via magnetic connection and the        laser light emitter attaches to the arm via magnetic connection.        CONCEPT 6. A method as in concept 1, wherein the adjusting steps        comprise adjusting a screw coupled with a captured ball to move        a portion of the positioning apparatus about a pivot.        CONCEPT 7. A method as in concept 1, further comprising using        the positioning apparatus to attach a bone cutting guide to the        tibia.        CONCEPT 8. A method as in concept 7, further comprising:    -   removing the positioning apparatus from the tibia and the        cutting guide; and    -   making at least one cut on the tibia guided by the cutting        guide.        CONCEPT 9. A method for positioning a bone cut on a tibia, the        method comprising:    -   coupling a bone cut positioning apparatus with a tibia;    -   coupling a laser light emitter with the positioning apparatus at        or near one end of an arm of the apparatus, such that when the        emitter is coupled with the apparatus is emits light;    -   adjusting the positioning apparatus in a varus/valgus        orientation to shine the emitted light approximately along a        midline of an anterior surface of the tibia;    -   coupling the laser light emitter with the positioning apparatus        at or near an opposite end of the arm, such that when the        emitter is coupled with the apparatus is emits light;    -   adjusting the positioning apparatus in an anterior/posterior        orientation to shine the light approximately along a midline of        a side of the tibia; and    -   adjusting the positioning apparatus up or down to select a        tibial bone resection level.        CONCEPT 10. A method as in concept 9, further comprising        attaching a tibial cutting guide to the tibia, using the        adjusted positioning apparatus.        CONCEPT 11. A method as in concept 10, further comprising:    -   removing the positioning apparatus from the tibia and the        cutting guide; and    -   making at least one cut on the tibia guided by the cutting        guide.        CONCEPT 12. A device for positioning a bone cut on a tibia, the        device comprising:    -   a tibial attachment member;    -   an arm attachable to the tibial attachment member and extending        in an arc of approximately 90 degrees;    -   a laser light emitter attachable to the arm at a first position        at or near one end of the arm an a second position at or near an        opposite end of the arm;    -   a varus/valgus adjustment member for moving the arm to direct        light emitted by the emitter in the first position approximately        along a midline of an anterior surface of the tibia;    -   an anterior/posterior adjustment member for moving the arm to        direct light emitted by the emitter in the second position        approximately along a midline of a side of the tibia; and    -   a bone resection level adjustment member for selecting a level        for resecting the tibia.        CONCEPT 13. A device as in concept 12, wherein the tibial        attachment member comprises independently movable medial and        lateral feet for contacting the medial and lateral articular        surfaces of the tibia.        CONCEPT 14. A device as in concept 12, wherein the varus/valgus        adjustment member comprises a first captured ball and captured        screw that rotates the tibial attachment member about a first        pivot point, and wherein the anterior/posterior adjustment        member comprises a second capture ball and captured screw that        rotates the tibial attachment member about a second pivot point.        CONCEPT 15. A device as in concept 12, wherein the laser light        emitting member attaches to the arm at the first position and        the second position via magnetic force.        CONCEPT 16. A device as in concept 15, wherein the arm attaches        to the tibial attachment member via magnetic force.        CONCEPT 17. A device as in concept 12, further comprising a        tibial cutting guide holder, wherein adjustments of the        adjustment members adjust a position of the cutting guide        holder.        CONCEPT 18. A device as in concept 12, further comprising a        depth gauge coupled with the bone resection level adjustment        member.        CONCEPT 19. A system for positioning a bone cut on a tibia, the        system comprising:    -   a tibial cutting guide; and    -   a tibial bone cut positioning device comprising:        -   a tibial attachment member;        -   an arm attachable to the tibial attachment member and            extending in an arc of approximately 90 degrees;        -   a laser light emitter attachable to the arm at a first            position at or near one end of the arm an a second position            at or near an opposite end of the arm;        -   a varus/valgus adjustment member for moving the arm to            direct light emitted by the emitter in the first position            approximately along a midline of an anterior surface of the            tibia;        -   an anterior/posterior adjustment member for moving the arm            to direct light emitted by the emitter in the second            position approximately along a midline of a side of the            tibia; and        -   a bone resection level adjustment member for selecting a            level for resecting the tibia.            CONCEPT 20. A system as in concept 19, wherein the tibial            cutting guide holder is moveable relative to the arm to move            the tibial cutting guide into contact with the tibia.            CONCEPT 21. A system as in concept 19, further comprising at            least one reference pin for removably attaching the tibial            attachment member of the guide positioning device to the            tibia.            CONCEPT 22. A system as in concept 19, further comprising at            least one cutting guide fastener for attaching the tibial            cutting guide to the tibia.            CONCEPT 23. A system as in concept 19, wherein the laser            light emitting member emits light in a linear or planar            configuration that may be directed along the tibia.            CONCEPT 24. A system as in concept 19, wherein the laser            light emitting member attaches to the arm at the first            position and the second position via magnetic force.            CONCEPT 25. A system as in concept 19, wherein the arm            attaches to the tibial attachment member via magnetic force.            CONCEPT 26. A system as in concept 19, further comprising at            least one depth gauge removably couplable with the bone cut            positioning device.            CONCEPT 27. A system as in concept 26, wherein the depth            gauge comprises a slidable member adjustable by moving the            bone resection level adjustment member and including at            least one indicator to indicate to a user when a desired            bone cut level has been reached.            CONCEPT 28. A system as in concept 27, wherein the at least            one depth gauge comprises multiple depth gauges provided as            a set, each gauge having an indicator at a different depth            for facilitating a different bone resection level.            CONCEPT 29. A system as in concept 28, wherein the multiple            depth gauges comprise three gauges having indicators at 3            mm, 9 mm and 10 mm of depth.            CONCEPT 30. A system as in concept 27, wherein the indicator            is selected from the group consisting of an LED, a colored            marker, a reflective marker and a tactile element.            Broadly this writing discloses at least the following            method.            A method for positioning a bone cut on a bone may involve:            coupling a bone cut positioning apparatus with a body bone;            adjusting the positioning apparatus in a varus/valgus            orientation relative to the body bone; adjusting the            positioning apparatus in an anterior/posterior orientation            relative to the body bone; and adjusting the positioning            apparatus up or down to select a bone resection level.

The invention claimed is:
 1. A method for positioning a bone cut on a tibia, the method comprising: coupling a bone cut positioning apparatus to a tibia, the positioning apparatus including a bone cutting guide; attaching a laser light emitter to a swing arm of the positioning apparatus, the attaching including activating the laser light emitter such that it can emit laser light; positioning the swing arm and the laser light emitter into a first orientation relative to the tibia; adjusting, with the swing arm and the laser light emitter in the first orientation, the positioning apparatus in a varus/valgus orientation relative to the tibia, including using emitted laser light from the laser light emitter to position the bone cutting guide in reference to an anterior surface of the tibia; positioning, by pivoting, the swing arm and the laser light emitter into a second orientation such that the laser light emitter can emit laser light to provide orientation along a medial or a lateral surface of the tibia; adjusting, with the laser light emitter in the second orientation, the positioning apparatus in an anterior/posterior orientation relative to the tibia, including using emitted laser light from the laser light emitter to position the bone cutting guide in reference to the medial or the lateral surface of the tibia; and adjusting the positioning apparatus up or down to select a tibial bone resection level wherein at least one of the adjusting the positioning apparatus operations includes adjusting a screw coupled with a captured ball to move a portion of the positioning apparatus about a pivot, the screw coupled with the captured ball via a threaded shaft through the captured ball.
 2. A method as in claim 1, wherein adjusting the positioning apparatus in the anterior/posterior orientation includes using emitted laser light from the laser light emitter to position the bone cutting guide in reference to the medial surface of the tibia.
 3. A method as in claim 1, wherein coupling the bone cut positioning apparatus to the tibia comprises: coupling a tibial attachment member with a proximal end of the tibia; and coupling the swing arm of the positioning apparatus with the tibial attachment member, wherein the swing arm pivots around the tibia approximately 90 degrees from the first orientation, anterior to the tibia, to the second orientation, lateral or medial to the tibia.
 4. A method as in claim 3, wherein the swing arm attaches to the tibial attachment member via a magnetic connection and the laser light emitter attaches to the swing arm via a magnetic connection.
 5. A method as in claim 1, further comprising using the positioning apparatus to couple the bone cutting guide to the tibia.
 6. A method as in claim 5, further comprising: making at least one cut on the tibia guided by the bone cutting guide.
 7. A method for positioning a bone cut on a tibia, the method comprising: coupling a bone cut positioning apparatus with a tibia; coupling a laser light emitter to the positioning apparatus at or near a first end of a swing arm of the apparatus, such that when the emitter is coupled with the apparatus it emits light; adjusting the positioning apparatus in a varus/valgus orientation to shine the emitted light approximately along a midline of an anterior surface of the tibia; pivoting the first end of the swing arm with the laser light emitter into a position adjacent to a side of the tibia; adjusting the positioning apparatus in an anterior/posterior orientation to shine the emitted light approximately along a midline of a side of the tibia; and adjusting the positioning apparatus up or down to select a tibial bone resection level wherein at least one of the adjusting the positioning apparatus operations includes adjusting a screw coupled with a captured ball to move a portion of the positioning apparatus about a pivot, the screw coupled with the captured ball via a threaded shaft through the captured ball.
 8. A method as in claim 7, further comprising attaching a tibial cutting guide to the tibia, using the adjusted positioning apparatus.
 9. A method as in claim 8, further comprising: removing the positioning apparatus from the tibia and the cutting guide; and making at least one cut on the tibia guided by the cutting guide.
 10. The method of claim 7, wherein coupling the laser light emitter to the positioning apparatus includes magnetically coupling the laser light emitter to the first end of the swing arm.
 11. The method of claim 10, wherein magnetically coupling the laser light emitter to the first end of the swing arm includes automatically activating the laser light emitter.
 12. The method of claim 7, further including removing the laser light emitter from the first end of the swing arm.
 13. The method of claim 12, wherein removing the laser light emitter from the first end of the swing arm automatically deactivates the laser light emitter. 